The present invention relates to the production of silane by reaction of silicon tetrafluoride with an alkali metal hydride.
While the production of silane from silicon tetrachloride has been known for many years, the corresponding reaction of silicon tetrafluoride appears in few references. The reaction of stoichiometric amounts of LiAlH.sub.4 with SiF.sub.4 in an ether solvent is reported by Padma et al. in J. Fluorine Chem 14(4) 327-29 (1979). British Pat. No. 909,950 (1962) reports reactions between alkali metal hydrides and silicon halides in ether solvents catalyzed by zinc salts, and alleges that silicon tetrafluoride is a suitable reactant.
Copending, commonly assigned U.S. Pat. No. 208,978 of Lefrancois (filed Nov. 21, 1980) and corresponding EPO Published Application No. 52,808 (June 2, 1982), report the reaction between silicon tetrafluoride and sodium hydride at high temperatures in selected aromatic ether solvents such as diphenyl ether. Poor yields are indicated for the same reactants in refluxing tetrahydrofuran. At the boiling point of diphenyl ether some yield loss of NaH to hydrogen gas is reported.